Amniotic fluid embolism to lung

Amniotic fluid embolism is a special type of pulmonary embolism where the embolus is comprised of amniotic fluid. It can be a highly fatal complication of pregnancy, with an 80% maternal mortality rate. 

It is thought to complicate 1/8000-80,000 pregnancies.

The classic clinical presentation is of abrupt dyspnoea, cyanosis, and shock, shortly followed by a cardiorespiratory arrest and severe pulmonary oedema. Some patients may present with an anaphylactic reaction caused by a hypersensitivity to the leukotrienes and arachnoid metabolites present in amniotic fluid. Central nervous system irritability producing convulsions is also considered a typical feature. 

It occurs when amniotic fluid is forced into the bloodstream through small tears in uterine veins during normal labour. However, in some cases, the placenta is disrupted by surgery or trauma.

Associations
  • approximately 40% of patients may suffer a consumptive coagulopathy 2
Plain radiograph

Non-specific but may have diffuse bilateral heterogeneous and homogeneous areas of increased opacity (can be indistinguishable from acute pulmonary oedema due to other causes).

CT

Chest CT may show diffuse ground glass opacities (similar to early stage of acute respiratory distress syndrome) and prominent hilar pulmonary vasculature 9.  CT findings are also not specific and difficult to distinguish from other causes of acute noncardiogenic or cardiogenic pulmonary oedema.

It was first reported by Ricardo Meyer in 1926 6.

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Article information

rID: 25265
Systems: Chest, Vascular
Tag: cases
Synonyms or Alternate Spellings:
  • Amniotic fluid embolism
  • Amniotic fluid emboli
  • Amniotic fluid embolism to lungs
  • Pulmonary amniotic fluid embolism
  • Amniotic fluid emboli (AFE)
  • Amniotic fluid embolism to the lungs

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